Fuse



April 22, 1924.

G. E. KEI-:FER

FUSE

Filed Nov. 21

. 1919 3 Sheets-5heet-2 GLENv E. KEEFER (idallwf April 22 1924 /NVENTo/e GLEN E. KEE/-j-EE `Pimm-d Aer. 22, 1924.

,UNITED `s'r.1\',rls.s PATENT: OFFICE.

GLEN nLGIN xnnrnn, or wns'rron'r, oOifimc'rctrry Assicnon rro CHARLES n.

xnnrnn COMPANY, Orj Wnsrroar, coNNEo'ricUna CORPORATION or cONNEc'TL,

vour;A

- rusia f Application illed November #1, 1919. Serial No: 839,654.

To all whom #may concern."

kBe it known that I, GLEN Emir: KEEFER,

a citizen ofthe UnitedStates of America, j

residing at Westport,"in the county oFa'ir- 6 field and vStatefyofv Connecticut, have invented certain newk and useful 'Improvements'in Fuses, of which the following isa speciication." f

l My invention relates to fuses, and articularly to cartridge fuses of the renews. le fuse link type,y the object of my invention being to provide an improved'construction which is economical to manufacture, simple to op-k crate, andy safe in service. f ll yIn theaccompanyin drawin Fi 1 is a broken si e elevationof a fuse in w ich my invention is embodied in'one form;

`Fig. 2 is an end elevation thereof, parv tially broken away;

, Fig.'3 is a plan of the gas screen; y

1 Fig. iis an end view with the blade contact` and cap removed; f Fig. v5 is any end levation showing the bridge opened to pgrmit' access to the interior of the ,fusee dy for ythe renewal of the fuse;

Fig. V6 is a longitudinal section through a fuse of di'erent type;

Fig.'7 is an end elevation thereof;

Fig. 8 is an end elevation with thecap removed;

Fig. 9 is a view similar to Fig. 5; and

f Fig. 10 is a plan of the screen.

, Fig. 11 isa perspective of a fuse showing the parts at one end detached and in positionfor assembly; f f

Fig. 12 is an end rview illustrating the shutter partiallyclosed; and

w Fig. y13 is a perspective of the fuseelernent alone.\'.' rIn the construction shown in 1r tOy 5,

the present fuse comprises a tubular cartridge-hodyv 15 of ber, or" other suitable in- 4l sulatin material, which servesfto house the renewa le uselink 16 passing longitudinally therethrou h. At each end of [the body a metallic errule 17 ris'secured in any suitablemanner,l as, for example, by crimp'- no ing .at 18, where ay permanent connection is o desired. This errule 17 has an end openying 19 which affords access to theinterior of the fuse chamber to rclean out the latter and to facilitate the replacement of a blown ,i y* 5s k'use link. 1 At one margnof the Opening 19 a rectangular way `2Ois out, through which` the fuselink passes. K

Normally closing the opening 19 is a bridge plate 21 freely pivoted on the pin 22' oarried'by the `ferrule 17. A second pin 23,

`also carried bythe ferrnle, serves asa stop,

which is engaged by the nose 24 of the bridge plate when the latter is swung into 'closed position, as shown in Figlie. It will be noted `that'in kthis' position thev fuse 16 is tially fills the latter. The bridge plate 21` is marginally notchedgat 25`to permit the reduced end 26 of the fuse link to be carried back in the Vchannel 27 formed in the threadvclosely-"confined in the way 2O and substan a ed'area 28 of theouter end of the ferrule 418..

` Each blade termina1'29' of the fuse is carA ried by a base plate 30, perforated at 31 to freelyengage the studs 22 and 23 which project beyond the bridge plate 21 and serve to maintain the blades 29 in alignment atl opposite ends of the fuse. In order to prevent escapefof flame when the fuse is blown,

a baflling .and cooling screen 32, slotted at 33, is pressed down over the 'blade 29 and rests upon the Outer face of its base plate 30. 'The parts are rigidly united and contact lis established between the fuse link and .thebase plate 30 of the blade 29 by means of 'screwed on the ferrule, and the parts are `clamped rigidly together, its skirt 36 holds --down the bent-over end 26 of the fuse link,

but doesnot wholly conceal the latter, thus leavingan exposed end 37, on which may be stampedthe rated capacity of the link. It

will alsobe noted that in the assembled posi-y tion of the parts an expansion chamber 38 is afforded-between the Outer 4face of the bridge plate 21 and the inner face of the base plate 30 ofthe terminal v29. From this chamber the gases are freeto escape through the holes 31 inthe base plate 30 and the screen 32,

while a restricted passageway is also aiorded l byk the loose fit f of the cooperating threaded areas of the ferrule and screwcap at 28. The passage 27 is baled by the corrugations 18, and by crimps in the end of the fuse link, if desired.

The construction shown in Figs. 6 to 10 diriers from that just described, principally in such obvious modifications as are incidental to the a laptation of the same ideas to ay cartridge fuse of the clip type. As in the lirst construction. this modification comprises an insulating body 15 having at each end a` terrulc 17 crimped at 18 into permanent engagement. therewith, and having an exterior threaded area 28 at its outer end. The bridge plate 2l is pivoted to the errule 17 by the stud Q2 and is halted by the stud 23 in closed position. It is also' provided with a notchV Q5, which registers with the. notch 27 in the fcrrule. to permit the fuse 16 to be carried over the bridge plate and turned down in the channel 27 beneath the screw `cap 39. The latter is provided with an end closure diaphragm 40 integral with the cap, but perforated at 4l to permit the escape of gases therethrough. lVithin the cap is a screen 42 which rests directly upon the bentove; fuse. end and establishes good electrical connection between the parts when the cap is screwed on the ferrule 17. In this construction. as in that first described, an expansion chamber 38 is aiiorded for the gases emerging from the fuse chamber. while the screen 42 prevents the escape of fiame through the holes 41. The bent-over end of the fuse carried beyond the skirt et the cap 39, and the rating of the Jfuse is indicated upon the exposed end 37 thereof.

The construction shown has several features or marked value. It will be noted thatl when the screw cap 34 is turned down hard, the bridge plate 21 is forced tirmly against the end tace of the terrule 17 and 'forms a substantial seal therewith. The fuse chamber is therefore practically closed except at the fuse passage 20, and this passage is substantially filled by the fuse itself. The channels of escape for the gas are quite restricted therefore, and suiiicient pressure is maintained in the chamber to smother at once the rc which tends to form on the blowing of the fuse. On the other hand, such gas as does escape passes into the expansion chamber 38, where it is somewhat `cooled before it passes out through the vents 31 or 41, While any flame is obstructed by the screen 32 or 42. This construction makes it possible/to carry out the capacity indicating end of the fuse to exposed position on the exterior of thefuse body. since theexpansion chamber and its end vents Vtake care ofthe Haine, and the latter has no tendency to blow out at the channel 26. Moreov r, the corrugations :it 18 tend `to baffle thepassageof gas at-'this point, an effect which may be'heightened by crimping the `fuse also vattbis point?. So. far @Sz I 3m: S-Wfeelo Cartridge fuse of thefrenewable type has heretofore been made in which the rating end of the fuse link can be carried out of the fuse chamber and exposed with impunity on the exterior of the Vfuse body. This is a feature of great practical value as an added safeguard against improper fuse installations, not only because inspection is easy. but also because it remains an uninjured telltale when the fuse is blown and responsibility for damage caused is to be traced.

The construction shown is simple and rugged, easy to manufactureand assemble. Obviously, however. the details of construction may be variously modified to attain the same end without departing from what I claim` as my invention. My underlying thought is to provide a vented expansion chamber communicating with the substantially sealed fuse chamber and provided with means to prevent the escape of flame. The end vents are screened. The side vent through the indicating tab channel is baled. The vent through the threads of the ferrule and cap is circuitous and prolonged, but in any case the vents from the expansion chamber, in which the gases are somewhat chilled, are sulicient to maintain this chamber at a pressure very much lower than that which exists in the fuse chamber.

I claim l. A cartridge fuse having a fuse chamber. a bridge piece pivotally secured nt one end thereof, a fuse link passing from the fuse chamber and bent at one end over said bridge piece in assembled position, a member bearing upon said bent-over fuse end and spaced thereby from the pivoted bridge piece to afford an expansion chamber, means for clamping said' member upon the fuse end. and means affording an -end vent for the gases generated by the melting of the fuse link in the fuse chamber.

2. A cartridge fuse having a fuse chamber. a bridge piece pivotally secured at one end thereof, a fuse link extending from the fuse chamber and bent over said bridge piece in assembled position, a member'bearing upon the bent-over end of said fuse link and spacedthereby from the pivoted bridge piece to afford an expansion chamber, said member lying in the'v path of 'escape of the gases from thevfuse chamber and causing the same to change direction, and an endf vent for theescape'of said gases generated by the melting of the fuse link in the fuse chamber. y, Y

3. A cartridge fuse comprising a chambered fuse body, ai ferrule aixed tothe end of said'body,a` closure memberpivoted'on the end` of sa-'d ferrule andcosing the llitL ter-savefor the fusepassagefwaya fusfe' link arranged in thefuse vchamber and' extending therefrom through;y said passageway and havingits end bent .lover said pivoted mem; ber in assembled position, a clamping memwraattaw i y way and causing the same to change direck30 ing casing aiordin a fusey chamber, a mea partial end closure yfor t kthe fuse link.

tion, together with mens for venting .the gases at the end of the fuse.

4'. In a cartrid e fuse, a fuse chamber, an end closure there or, ar fuse extending from the fuse .chamberadjacent the lmargin of said end closure, the endof the kfuse link extending across ksaid closure member to exposed position on the exterior of the'fuse chamber, a baffling member bearing on the bent-over'end of the fuse link, and means for clamping said bailing member in position, together with a vent for4 the gases, said vent being located at the end of the fuse at a point remote from ythe exposed end of 5. In a cartridge fuse, a tubular insulatin casing, affordmg a fuse chamber,.a metaic ferrule secured at yone end of said ferrule, and a bridge piece pivoted on said ferl` rule and afordinga support over Which'one lnk may be bent.

tallic ferrule'secure at one end ofthe chamber and having a diaphragxm which aords e fuse chamber,

p a bridge piece pivoted on said diaphragm of the fuse chamber, save for the fuse pas-r and co-operating therewith to close the end sageway, in combination'with a fuse link arranged in said fuse chamber and extending therefrom between adjacent mar ins of the bridge piece and diaphragm, sai link having an oset end overlying the bridge ieoe, and a bailling member bearin on sai offset end of the fuse link and o structing the free passage of gases from the fuse chamber through the fuse passageway, together with an en ventfor the fuse chamber. Y 1'.y As an end element of a cartridge fuse, a metallic ferrule adapted to be secured to the end of the fuse body, said ferrule having a partial end closure diaphragm for the` yfuse chamber but affording an opening through which access to the fuse chamber may be had, together with a shutter pivoted on said end closure diaphragm serving to complete the closure of the end opening in the ferrule except for a fuse passageway Y therethrough.

8. A cartridge fuse having a tubular body of insulating material, a ferrule permanently affixed thereto and forming a partial end closure with central opening to afford access to the fuse chamber, and throu h which c the end of the fuse is passed, a bri ge piece 'pivoted thereon and normally closing said central opening except for the fuse passageway, and across which the fuse end is angled in the assembled fitting, in combination with a cooperating closure member kclamping said angled-over end of the fuse and spaced thereby from the brid e piece to aiord an expansion chamber, sai closure member being apertured to afford an end vent for the fuse.

9. A cartridge fuse having a tubular body of insulating material, an exteriorly channeled errule permanentlyy aiixed thereto and forming a partial end closure with central opening to aiord access to the fuse chamber and through which theend of the fuse is passed, a bridge piece pivoted thereon and. normally closing said central opening except for the fuse passageway, and across which the fuse end is angled and bent back ythrough said ferrule channel to exposed position on the exterior of the fuse body, in combination with a screw-clam ed end closure bearing on said angled-over use end and s aced thereby from the bridge piece to a ord an expansion chamber, said closure member being apertured to aord an end vent for the Vfuse, and the screw clamped end closure engaging the threaded area of the ferrule.

In testimony whereof I have signed my name to this specification.

- GLEN ELGIN KEEFJER. 

